This is an excerpt from a March 2012 briefing paper by Friends of the Earth, ‘Japan’s nuclear scandals and the Fukushima disaster’, online at https://nuclear.foe.org.au/power/
Was TEPCO − operator of the Fukushima Dai-ichi nuclear plant in Japan − responsible for the nuclear disaster which began on March 11 last year? Or was the disaster the result of unfortunate but unavoidable natural disasters which could not be anticipated − an ‘Act of God’?
Many nuclear advocates want to absolve TEPCO from responsibility for the March 2011. However there is an abundance of evidence that TEPCO did not adequately protect the Fukushima plant against earthquake and tsunami risks. In particular, the failure to adequately protect back-up power generators was a direct cause of the nuclear disaster that began unfolding shortly after the other two disasters on March 11 − the earthquake and the tsunami.
The greatest problem was the location of most of the water-cooled generators in the basement of a poorly-protected turbine building. Fukushima Dai-ichi was equipped with 13 emergency diesel generators, one of which was out of service for maintenance on March 11. TEPCO had three air-cooled backup generators located 10−13 metres above sea level. In addition there were the 10 water-cooled generators.
After the March 11 earthquake and tsunami, only one of the air-cooled generators, which sat 13 metres above sea level, was still functional after the tsunami (it helped protect reactors #5 and #6). The other two air-cooled generators were rendered useless by the tsunami despite being 10 metres above sea level. All 10 of the plant’s water-cooled generators were inundated by the tsunami.
Without back-up generators, it was only a matter of time before the situation spiralled out of control as it so dramatically did with a succession of meltdowns, fires and explosions in the days after March 11.
Experts speak with one voice: this was a man-made disaster not an Act of God. The Investigation Committee established by the Japanese government last year said: “TEPCO did not implement measures against tsunami as part of its Accident Management strategy. Its preparedness for such accident as severe damage at the core of reactor as a result of natural disasters was quite insufficient.”
A June 2011 report by the International Atomic Energy Agency found that there were “insufficient defense-in-depth provisions” for tsunami hazards at Fukushima and that “severe accident management provisions were not adequate to cope with multiple plant failures.”
TEPCO lacked “common sense” and “absolutely should have known better,” said Dr Costas Synolakis, a US engineering professor with expertise in tsunami modelling.
Former TEPCO executive Masatoshi Toyota said: “Backup power generators are critical safety equipment, and it should’ve been a no-brainer to put them inside the reactor buildings. It’s a huge disappointment that nobody at TEPCO − including me − was sensitive enough to notice and do something about this discrepancy.”
Another former TEPCO executive said: “We took it for granted that the quake-resistant design of our Fukushima and other nuclear plants was fail-safe. But I now doubt how serious we were about preparing for a severe disaster. If only we’d put the backup generators on even higher ground away from the reactors, the Nos. 1 to 4 reactors might not have been damaged.”
Former TEPCO engineer Toshio Kimura said: “I asked my boss back in the late ’90s what would happen if a tsunami hit the Fukushima reactors. I said surely a meltdown will happen. He said ‘Kimura, you are right’. But it was made clear that the issue of a big tsunami was taboo. … If they’d moved the emergency diesel generators to a position above the expected tsunami level it would have cost the company a lot. So nobody proposed it. … A few years later I quit the company because of its culture of cover-ups.”
Another TEPCO engineer said that when he was preparing for a government inspection in 1987, the inconsistent placement of the generators “stood out like a sore thumb.”
For many years, TEPCO either denied the possibility of an earthquake and tsunami of March 11 proportions or argued that such events were so improbable that they could be ignored. In 2001, TEPCO submitted a document on tsunami preparedness to the Nuclear Safety Agency − a one-page document.